remove index.rst

doc/index.rst

-.. format documentation master file, created by
-   sphinx-quickstart on Tue Dec 18 06:46:16 2012.
-   You can adapt this file completely to your liking, but it should at least
-   contain the root `toctree` directive.
-
-Welcome to format's documentation!
-==================================
-
-Contents:
-
-.. toctree::
-   :maxdepth: 2
-
-   format
-
-Indices and tables
-==================
-
-* :ref:`genindex`
-* :ref:`modindex`
-* :ref:`search`
-